It is crucial that a contour survey is made of the block of land.
Some of the common building survey terms are:

A.H.D. or Australian Height Datum

A consistent measure is taken from the mean sea level. 


A permanent reference point on a block of land used when a survey is carried out.

Boundary Survey/Peg Out

The exact boundaries of the block are identified as sometimes fences (and or existing structures), may be built over correct boundary lines on your newly purchased block of land This type of survey/peg out is often accompanied by the below Contour Survey.

Contour Survey

Measures and records the slope or flatness of the land.

Identification Survey

This survey identifies the exact location of existing buildings, trees and features and usually shows the distance to the property boundaries.'Peg Out Survey
Positions are marked on site to locate where a new dwelling will be built.

N.G.L. or Natural Ground Level

A measure to determine the level of land as it existed when the first survey showing the lot was registered or if that level is not known, a reasonable estimate of that level (source: Queensland Development Code). Some jurisdictions (such as the Australian Capital Territory) used the term Datum Ground Level.

R.L. or Reduced Level Height

A datum point is adopted and then used as the vertical distance from a survey point.